Of course, as (with Canavan) I have been at some expense of time to prove, virtually ALL cases of psychosis (as autopsied) are in a microscopic sense abnormal as to kidneys.[7] But only about a third exhibit GROSS interstitial nephritis, arguing a certain severity of process. The above cases, it will be observed, fall into the GROSS class in respect to renal lesions.
Without laying too much stress on such results, it is worth while to say that, whereas most workers might be willing to surmise that metabolic or catabolic disorder must affect the sense of well-being, I must confess that the discovery of so much gross kidney disease in a group selected on other grounds filled me with a certain surprise.
The literature is not without suggestions as to the possible correlation of renal and mental disorder. Ziehen,[8] for example, remarks that nephritis brings about mental disease in two ways,—through vascular changes which very frequently accompany chronic nephritis and other uremic changes in the blood. Inasmuch as we know that creatin, creatinin and potassium salts irritate the animal cortex, Ziehen notes that psychopathic phenomena may occur in man as a result of slight uremic changes. According to Ziehen, most of these nephritic psychoses run the course of what he calls hallucinatory paranoia (it may be remembered that Ziehen counts among paranoias a number of acute diseases and even so-called Meynert's amentia). Chronic nephritis, as well as acute diabetes and Addison's disease are thought by Ziehen to produce certain chronic forms of mental defect which he terms autotoxic dementia, but he regards most of these cases as really cases of arteriosclerotic dementia.
It does not appear that Wernicke[9] has considered renal correlations systematically.
Kraepelin[10] mentions the epileptiform convulsions of uremia as well as delirious and comatose conditions, especially those in advanced pregnancy. These uremic conditions may be both acute and chronic. But Kraepelin has not been able to convince himself of the existence of a clearly defined uremic insanity unless the delirious condition just mentioned may be regarded as such
Binswanger[11] states that the mental disorders occurring in acute and chronic nephritis are either toxemic psychoses on uremic bases, or due to arteriosclerosis. In the latter cases, he states that the disease pictures are as a rule characterized by grave disturbances of emotions, chiefly of a depressive character. He adds that these are all too frequently the forerunners of arteriosclerotic brain degeneration.
A brief mention of renal disease in the general etiology of mental disease is made by Ballet.[12] Ballet states that Griesinger's opinion that renal disease had little importance in the etiology of mental disease and that no one would count the cerebral symptoms of Bright's disease as mental is no longer held. Ballet enumerates a number of works upon so-called folie brightique which tend to prove that acute or chronic Bright's disease gives rise either to melancholic disorder or alternately to maniacal and melancholic disorder. How the mental disease is produced is doubtful. Ballet holds that all the various psychopathic disorders resulting from Bright's disease are autotoxic. Renal disease like heart disease is only capable of awakening a latent predisposition or liberating a constitutional psychosis, unless it is merely effecting a species of intoxication.
It cannot be doubted that the relation of kidney disorder to mental disorder is worth intensive study, of which the present communication is merely a fragment. Progress will be of course impeded by the fact that upon microscopic examination, practically all cases of mental disease coming to autopsy show renal disease of one or other degree; in fact, it is perhaps possible to show a higher correlation of renal disease with mental disease than of brain disease to mental disease. Perhaps something can be obtained if we limit ourselves to a study of cases with pronounced somatic renal symptoms and signs, cases with the renal facies and the like.
As to the question of phthisis and mental disease, Ziehen remarks that the tuberculous are often observed to be optimistic but that other cases show a hypochondriacal depression with egocentric narrowing of interests. He speaks of a sort of rudimentary delusional disorder looking in the direction of jealousy in certain cases. Pronounced mental disorder occurs rarely in tuberculosis, according to Ziehen, and leads either to melancholia or to hallucinatory states of excitement, resembling the deliria of exhaustion or inanition. Acute miliary tuberculosis may produce the impression of a general paresis or of an amentia in Meynert's sense. The inanition delirium of tuberculosis resembles that of carcinosis and malaria.
Kraepelin regards tuberculosis as of very slight significance in the causation of insanity, despite the fact that slight changes in mood and in voluntary actions frequently accompany the course of the disease. Irritability, depression and sensitiveness, incomprehensible confidence and desire to undertake various tasks, pronounced selfishness, sexual excitement and jealousy are the traits of mental disorder in tuberculosis.